A revolver made in the US for soldiers fighting in World War II made its way to Australia and was used in the terror-inspired shooting of Curtis Cheng over 60 years later.
As the NSW Supreme Court terror retrial continued against accused Mustafa Dirani on Thursday, crown prosecutor David Staehli SC said the Smith & Wesson gun used to murder Mr Cheng in 2015 was never registered in Australia.
There was no evidence of how the "old-style revolver" got from the United States to Australia before it was allegedly purchased by Dirani and Raban Alou and handed to 15-year-old Farhad Mohammad at Parramatta Mosque on October 2, 2015.
"After the gun left the factory in 1942, nothing was heard of it until it regrettably turned up ... in the hands of Mr Farhad after he shot Mr Cheng," Mr Staehli said.
Mr Cheng was shot in the back of the head by Farhad who had walked to NSW Police Headquarters from the mosque.
The gun could have been worth over $3000 because of its value to criminals, the barrister said.
"The gun's never been seen by law enforcement or recorded and thus it is a clean gun."
However, he told jurors there was no evidence of how much Dirani and Alou paid when they obtained it from Talal Alameddine at Merrylands Park the morning of the attack.
Around the same time as the pistol was obtained, Alou was allegedly recorded asking those he knew, including Dirani, to borrow small amounts of cash which may or may not have been used to pay for the firearm.
Mr Staehli said Alou and another man Milad Atai had "shopped around" for a gun with two men, simply known as X2 and X3 in the trial, but were unsuccessful until they procured the weapon from Alameddine.
Alou and Atai also allegedly tried to get an Islamic State flag made before the attack, although there is no direct evidence showing what the flag would have been used for.
Alou was already under police surveillance at the time, with a listening device in his car and on his phone, and officers following him through Sydney's streets.
Dirani is not said to have taken part in identifying potential gun dealers, procuring money for the firearm, or trying to secure an ISIS flag.
However, the Crown claims the Marsfield man assisted in obtaining the pistol from Alameddine just before it was handed over to Farhad on October 2.
Dirani faces one count of conspiring with others to do an act of terrorism and a back-up charge of supplying a firearm to Alou as an unauthorised person.
He has pleaded not guilty to both counts, with defence barrister Nathan Steel saying his client denied any involvement in the plot.
"Mr Dirani's position in this trial is that he was not a party to the conspiracy and he had not agreed to it," Mr Steel told the jury.
Dirani did not dispute that a terrorist attack had occurred but says he was not around when the gun was handed over and had simply gone with Alou on October 2 to get something to eat.
Alou met Alameddine at Merrylands Park alone that day after the accused left to meet a friend in Cherrybrook, the jury heard.
"It is the defence case that this is the likely time that the firearm was supplied," Mr Steel said.
While Dirani had shared extremist content online, this did not mean he had agreed to take part in the terrorist plot, the jury was told.
He asked jurors to put aside any strong emotional reactions they had to terrorist conduct, and deal with the case calmly, rationally and without prejudice.
"I simply ask at this stage that you do keep an open mind, that you don't jump to conclusions," he said.
The hearing with Justice Deborah Sweeney continues.
